Dielectric Waveguide Radar Signal Distribution

ABSTRACT

A system is provided for transmitting sub-terahertz electro-magnetic radio frequency (RF) signals using a dielectric waveguide (DWG) having a dielectric core member surrounded by dielectric cladding. Multiple radar signals may be generated by a radar module that is coupled to a vehicle. A set of DWG segments may be used to transport the radar signals to various launching structures placed in various locations of the vehicle.

CLAIM OF PRIORITY UNDER 35 U.S.C. 119 ((A) FOREIGN, (E) PROVISIONAL)

The present application claims priority to and incorporates by referenceU.S. Provisional Application No. 62/115,499, (attorney docketTI-75868PS) filed Feb. 12, 2015, entitled “DIELECTRIC (PLASTIC)WAVEGUIDE RADAR SIGNAL SURROUND DISTRIBUTION”.

FIELD OF THE INVENTION

This invention generally relates to vehicular radar systems, and inparticular to the use of dielectric waveguides to distribute radarsignals throughout a vehicle.

BACKGROUND OF THE INVENTION

A new class of safety systems, referred to as advanced driver assistancesystems (ADAS), has been introduced into automobiles to reduce humanoperation error. These systems are enabled by smart sensors basedprimarily on millimeter-wave automotive radars. The proliferation ofsuch assistance systems, which may provide functionality such asrear-view facing cameras, electronic stability control, and vision-basedpedestrian detection systems, has been enabled in part by improvementsin microcontroller and sensor technologies. Enhanced embeddedradar-based solutions are enabling complementary safety features forADAS designers.

In an automotive radar system, one or more radar sensors may be used todetect obstacles around the vehicle and the speeds of the detectedobjects relative to the vehicle. A processing unit in the radar systemmay determine the appropriate action needed, e.g., to avoid a collisionor to reduce collateral damage, based on signals generated by the radarsensors. Current automotive radar systems are capable of detectingobjects and obstacles around a vehicle, the position of any detectedobjects and obstacles relative to the vehicle, and the speed of anydetected objects and obstacles relative to the vehicle. Via theprocessing unit, the radar system may, for example, alert the vehicledriver about potential danger, prevent a collision by controlling thevehicle in a dangerous situation, take over partial control of thevehicle, or assist the driver with parking the vehicle.

Currently, an integrated circuit (IC) containing a radar transceiver maybe placed at each location in a vehicle where a radar signal is needed.For example, three ICs may be located on the front of a vehicle (middleand both corners) to provide forward looking coverage. Additional ICsmay be deployed on the sides and rear of the vehicle.

Many parking assist systems currently rely on ultrasonic transducers.Ultrasonic transducers require a hole to be provided in the bumper orfender of the vehicle for each transducer. A typical system includesthree or four transducers at the rear of a vehicle, which require threeor four unsightly holes in the rear body part of the vehicle.

In electromagnetic and communications engineering, the term waveguidemay refer to any linear structure that conveys electromagnetic wavesbetween its endpoints. The original and most common meaning is a hollowmetal pipe used to carry radio waves. This type of waveguide is used asa transmission line for such purposes as connecting microwavetransmitters and receivers to their antennas, in equipment such asmicrowave ovens, radar sets, satellite communications, and microwaveradio links.

A dielectric waveguide employs a solid dielectric core rather than ahollow pipe. A dielectric is an electrical insulator that can bepolarized by an applied electric field. When a dielectric is placed inan electric field, electric charges do not flow through the material asthey do in a conductor, but only slightly shift from their averageequilibrium positions causing dielectric polarization. Because ofdielectric polarization, positive charges are displaced toward the fieldand negative charges shift in the opposite direction. This creates aninternal electric field which reduces the overall field within thedielectric itself. If a dielectric is composed of weakly bondedmolecules, those molecules not only become polarized, but also reorientso that their symmetry axis aligns to the field. While the term“insulator” implies low electrical conduction, “dielectric” is typicallyused to describe materials with a high polarizability; which isexpressed by a number called the relative permittivity (εk). The terminsulator is generally used to indicate electrical obstruction while theterm dielectric is used to indicate the energy storing capacity of thematerial by means of polarization.

Permittivity is a material property that expresses a measure of theenergy storage per unit meter of a material due to electric polarization(J/V̂2)/(m). Relative permittivity is the factor by which the electricfield between the charges is decreased or increased relative to vacuum.Permittivity is typically represented by the Greek letter ε. Relativepermittivity is also commonly known as dielectric constant.

Permeability is the measure of the ability of a material to support theformation of a magnetic field within itself in response to an appliedmagnetic field. Magnetic permeability is typically represented by theGreek letter μ.

The electromagnetic waves in a metal-pipe waveguide may be imagined astravelling down the guide in a zig-zag path, being repeatedly reflectedbetween opposite walls of the guide. For the particular case of arectangular waveguide, it is possible to base an exact analysis on thisview. Dielectric waveguide guides the wave similar to a metal waveguidebut provides a lower loss and more flexible alternatives. A multidielectric waveguide with a metal shield is also possible.

BRIEF DESCRIPTION OF THE DRAWINGS

Particular embodiments in accordance with the invention will now bedescribed, by way of example only, and with reference to theaccompanying drawings:

FIG. 1 is a plot of wavelength versus frequency through materials ofvarious dielectric constants;

FIGS. 2 and 3 are an illustrations of an example dielectric waveguide(DWG);

FIGS. 4-7 are illustrations of an exemplary radar distribution systemwithin a vehicle using DWGs;

FIG. 8 illustrates placement of a radar antenna adjacent a vehicle bodypart;

FIGS. 9-10 are illustrations of a radar module for use in a vehicle;

FIGS. 11-12 are examples of DWG connectors;

FIG. 13 is a block diagram of a radar system integrated circuit thatincludes multiple radar transmitters and receivers; and

FIG. 14 is a flow chart illustrating distribution of radar signalswithin a vehicle.

Other features of the present embodiments will be apparent from theaccompanying drawings and from the detailed description that follows.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Specific embodiments of the invention will now be described in detailwith reference to the accompanying figures. Like elements in the variousfigures are denoted by like reference numerals for consistency. In thefollowing detailed description of embodiments of the invention, numerousspecific details are set forth in order to provide a more thoroughunderstanding of the invention. However, it will be apparent to one ofordinary skill in the art that the invention may be practiced withoutthese specific details. In other instances, well-known features have notbeen described in detail to avoid unnecessarily complicating thedescription.

A dielectric waveguide (DWG) may be used as a medium to communicate chipto chip in a system or system to antenna, for example. Using a DWG cableto distribute radar signals between a radar module and radar antennasmay provide a low cost interconnect solution. Embodiments of thisdisclosure provide a way to interface multiple radar antennas to asingle radar module, as will be described in more detail below.

The low cost of DWG components may allow a parking assist system to beimplemented using a single radar module and multiple radar antennasinterconnected via DWGs at a price that is competitive with anultrasound system. A single radar IC in such a system may provide 180degree coverage across the rear of a vehicle, for example. A radar basedparking assist system does not require unsightly holes in the vehiclesbody components. Ultrasonic parking assist systems are limited to acoverage distance of about 10 m, while radar systems operating in the77-81 GHz band may easily extend coverage to a distance of 40 m or morewith high resolution imaging.

The wavelengths of radar signals are short enough that signal lines thatexceed a short distance may act as an antenna and signal radiation mayoccur; the lines would also be very lossy at such high frequencies duethe skin effect losses of the metal lines, therefore it is not practicalto distribute radar signals over a distance using conventionalconductive wires. FIG. 1 is a plot of wavelength versus frequencythrough materials of various dielectric constants. As illustrated byplot 102 which represents a material with a low dielectric constant of3, such as a typical printed circuit board, a 100 GHz signal will have awavelength of approximately 1.7 mm. Thus, a signal line that is only 1.7mm in length may act as a full wave antenna and radiate a significantpercentage of the signal energy. In fact, even lines of λ/10 are goodradiators, therefore a line as short as 170 um in a printed circuitboard may act as a good antenna at this frequency. Wavelength typicallydecreases in materials with higher dielectric constants, as illustratedby plot 104 for a dielectric constant of 4 and plot 106 for a dielectricconstant of 10, for example.

Waves in open space propagate in all directions, as spherical waves. Inthis way they lose their power proportionally to the square of thedistance; that is, at a distance R from the source, the power is thesource power divided by RA2. A low-loss wave guide may be used totransport high frequency signals over relatively long distances. Thewaveguide confines the wave to propagation in one dimension, so thatunder ideal conditions the wave loses no power while propagating.Electromagnetic wave propagation along the axis of the waveguide isdescribed by the wave equation, which is derived from Maxwell'sequations, and where the wavelength depends upon the structure of thewaveguide, and the material within it (air, plastic, vacuum, etc.), aswell as on the frequency of the wave. Commonly-used waveguides are onlyof a few categories. The most common kind of waveguide is one that has arectangular cross-section, one that is usually not square. It is commonfor the long side of this cross-section to be twice as long as its shortside. These are useful for carrying electromagnetic waves that arehorizontally or vertically polarized.

A waveguide configuration may have a core member made from dielectricmaterial with a high dielectric constant and be surrounded with acladding made from dielectric material with a lower dielectric constant.While theoretically, air could be used in place of the cladding, sinceair has a dielectric constant of approximately 1.0, any contact byhumans, or other objects may introduce serious discontinuities that mayresult in signal loss or corruption. Therefore, typically free air doesnot provide a suitable cladding.

For the exceedingly small wavelengths encountered for sub-THz radiofrequency (RF) signals, dielectric waveguides perform well and are muchless expensive to fabricate than hollow metal waveguides. Furthermore, ametallic waveguide has a frequency cutoff determined by thecross-sectional size of the waveguide. Below the cutoff frequency thereis no propagation of the electromagnetic field. Dielectric waveguidesmay have a wider range of operation without a fixed cutoff point.However, a purely dielectric waveguide may be subject to interferencecaused by touching by fingers or hands, or by other conductive objects.Metallic waveguides confine all fields and therefore do not suffer fromEMI (electromagnetic interference) and cross-talk issues; therefore, adielectric waveguide with a metallic cladding may provide significantisolation from external sources of interference.

US Patent Application publication number US 2014-0287701 A1, filed Apr.1, 2013, entitled “Integrated Circuit with Dipole Antenna Interface forDielectric Waveguide” is incorporated by reference herein. Variousconfigurations of dielectric waveguides (DWG) and interconnect schemesare described therein. Various antenna configurations for launching andreceiving radio frequency signals to/from a DWG are also describedtherein.

US Patent Application publication number US 2014-0240187 A1, filed Apr.1, 2013, entitled “Dielectric Waveguide with Non-planar InterfaceSurface” is incorporated by reference herein. Various configurations ofDWG sockets and interfaces are described therein.

Fabrication of DWGs using 3D printing is described in more detail in USPatent Application US 2015-0295297 A1, filed Sept. 26, 2014, “ MetallicWaveguide with Dielectric Core,” is incorporated by reference herein.

U.S. patent application publication Ser. No. 14/865,552, filed Sep. 25,2015, entitled “Dielectric Waveguide Socket” is incorporated byreference herein. Various configurations of DWG sockets and launchingstructures are described therein.

FIG. 2 illustrates a DWG 200 that is configured as a thin ribbon of acore dielectric material 212 surrounding by a second dielectric claddingmaterial 211. The core dielectric material has a dielectric constantvalue εk1, while the cladding has a dielectric constant value of εk2,where εk1 is greater than εk2. In this example, a thin rectangularribbon of the core material 212 is surrounded by the cladding material211. For sub-terahertz signals, such as in the range of 130-150gigahertz, a core dimension of approximately 0.5 mm×1.0 mm works well.Radar signals used in ADAS are typically in the 76-81 GHz band. A DWGwith a core that is approximately 0.5-1.0 mm×2.0 mm works well for thisfrequency band. For a lower frequency parking assist system in the 24GHz range, a DWG with a core that is approximately 3 mm×6 mm would workwell.

FIG. 3 is an illustration of an exemplary DWG 300 that has two cores312, 313 surrounded by a common cladding 311. Core 313 may have adielectric constant vale εk3 that is different from the dielectric valueεk1 of core 312, for example, or they both have the same dielectricconstant value.

While two DWG configurations are illustrated by FIGS. 2, 3, otherconfigurations may include additional numbers of cores, conductive wiresin addition to the dielectric cores, etc. While rectangular cores areillustrated herein, other embodiments of this disclosure may use coreshaving other shapes, such as square, round or oval, for example.Additional layers of dielectric material or conductive material may beused to provide mechanical protection or to reduce signal loss orinterference, for example.

Flexible DWG cables may be fabricated using standard manufacturingmaterials and fabrication techniques. These cable geometries may bebuilt using techniques such as: drawing, extrusion, or fusing processes,which are all common-place to the manufacture of plastics.

FIG. 4 is an illustration of an automobile 400 equipped with multipleradar antennas 401-406 coupled to a single radar module 410 via multipleDWG cables 421-426. Long range radar (LRR) may be used for applicationssuch as automatic cruise control. Medium rang radar (MRR) typically usea narrow beam and must detect high relative velocities. MRR may be usedfor applications such as: braking, intersection detection, pedestriandetection, and reverse cross traffic alerts, for example. Short rangeradar (SRR) typically uses a wide beam with large angular separation toprovide good distance resolution. SRR may be used for applications suchas: parking, lane change, and blind spot monitoring, and pre-crashalerts, for example.

By using DWG (plastic) links 421-426, a single RF Radar Chip 410 may beused, for all six radar antennas. This allows reuse of manyRF/Analog/Baseband/DSP circuits for all channels. Losses in the DWGlinks are minimal, typically a few db due to coupling losses, and may becompensated by increased sensitivity and output power from the radarchip.

FIG. 5 is an illustration of an exemplary radar system having a singleradar transceiver integrated circuit (IC), multiple radar launchstructures 501-504, and interconnections between the radar IC and thelaunch structure via DWGs 521-524. In this example, radar IC has fourreceiver channels 511-514 and three transmitter channels 515-517. Anexample radar transceiver will be described in more detail later.

In this example, each launch structure 501-503 is coupled to radar IC510 via a dedicated DWG. For example, transmit antenna 502 is coupled toa transmit port 515 on IC 510 via DWG 522. Similarly, receive antenna501 is coupled to a receive port 511 on IC 510 via DWG 521.

FIG. 6 is a pictorial illustration of a bumper 631 of a vehicle with aparking assist radar system mounted on the bumper. In this example, aradar module such as module 510 from FIG. 5 is mounted such thatreceiver ports 512, 513 and transmit port 516 are located adjacentbumper so that a radar signal may be transmitted directly through thebumper 631 by device 510, as indicated at 642. Radar launchingstructures 601 and 602 are coupled to respective ports on device 510using DWGs 621 and 622 and are configured to transmit radar signalsdirectly through the bumper as indicated at 641 and 642.

Typically, a radar antenna may form a useful radiation pattern over anarea of approximately +/−60-80 degrees. Thus, in the example of FIG. 6,a single radar IC can cover the entire 180 degree view in front or rearof a vehicle using multiple launching structures that are interconnectedusing inexpensive DWGs. As mentioned above, holes through the bumper foreach antenna are not required, as are required for an ultrasoundtransducer.

FIG. 7 is a pictorial illustration of a bumper 731 of a vehicle with aparking assist radar system mounted on the bumper. In this example, aradar module such as module 510 from FIG. 5 is mounted such thatreceiver ports 512, 513 and transmit port 516 are located adjacentbumper so that a radar signal may be transmitted directly through thebumper 731 by device 510, as indicated at 742. Radar launchingstructures 701 and 702 are coupled to respective ports on device 510using DWGs 721 and 722 and are configured to transmit radar signalsdirectly through the fenders 732, 733 as indicated at 741 and 742. Inthis example, beam steering may be used to widen the radiation pattern742.

In this manner, more that a 180 degree view of the front or rear of avehicle may be obtained using multiple launching structures that areinterconnected using inexpensive DWGs. As mentioned above, holes throughthe bumper and fender for each antenna are not required, as are requiredfor an ultrasound transducer.

FIG. 8 illustrates placement of a radar antenna 801 adjacent a vehiclebody part 831. In this example, body part 831 may be a bumper, fender,door panel, etc. As mentioned before, there is no need to provide a holethrough the panel since radar radiation is capable of penetrating mostmaterials used for vehicle construction.

Radiation launching structure 801 may be any of several types of hornantennas, dipole antenna, Vivaldi antenna, etc. that are now known orlater developed. Typically, the launching structure may be placed intight contact with an inner surface of the panel, as illustrated here,or spaced away from the inner surface of the panel. When the launchingstructure is spaced away from the body part, there may be some signalreflection that may require compensation, for example.

DWG cable 821 may be coupled to launching structure 801 using aconnector device 842. Similarly, connecter device 841 may be provided toallow coupling of DWG 841 to another DWG cable or to a radar module, asdescribed above. Alternatively, launching structure 801 may be formed asa permanent part of the end of DWG 821, for example.

FIG. 9 is an illustration of an example radar module 900 for use in avehicle. In this example, a radar SOC 910 is a known or later developedradar SOC, such as SOC 510 of FIG. 5, for example. SOC 910 may bemounted on a substrate 951, such as a printed circuit board or otherknown or later developed substrate. DWG segments, such as DWG 921, 922may be coupled to radar ports on SOC 910. The ends of the DWG segmentsmay be terminated in connectors, such as connector device 941, 942, toallow easy coupling to other DWG segments that are connected to variousradar launching structures, as discussed above in more detail.

There may be additional ICs mounted on substrate 951 to control SOC 910and to provide ADAS functional operations. Communication interfaces maybe provided to communication with other systems in the vehicle, such asbraking systems, steering, engine control, etc.

This substrate may range from an integrated circuit (IC) die, asubstrate in a multi-chip package, a printed circuit board (PCB) onwhich several ICs are mounted, etc., for example. Substrate 951 may beany commonly used or later developed material used for electronicsystems and packages, such as: silicon, ceramic, Plexiglas, fiberglass,plastic, etc., for example. The substrate may be as simple as paper, forexample. The entire module 900 may be encapsulated or otherwise enclosedto provide mechanical and climatic protection.

FIG. 10 is an illustration of another example radar module 1000 for usein a vehicle. In this example, a radar SOC 1010 is a known or laterdeveloped radar SOC, such as SOC 510 of FIG. 5, for example. SOC 1010may be mounted on a substrate 1051, such as a printed circuit board orother known or later developed substrate. DWG segments, such as DWG1021, 1022, 1025, 1026 may be coupled to radar ports on SOC 1010. Theends of the DWG segments may be terminated in connectors, such asconnector device 1041, 1042, to allow easy coupling to other DWGsegments that are connected to various radar launching structures, asdiscussed above in more detail.

In this example, a toroidal splitter 1061 and/or a toroidal coupler 1062may be used to provide DWG interconnect options. For example, DWGsegment 1021 may be coupled to a transmitter port on SOC 1010. Toroidalsplitter 1061 may be used to divide a single radar signal coming fromSOC 1010 into two signals. Additional splitters may be added to provideadditional output radar signals. Toroidal splitter 1061 may beconstructed using well known principles. For example, a known “rat racesplitter” operates by placing output ports at precise wavelengthlocations on the toroidal ring. Other known or later developed splittersmay be used to increase the number of outputs or to combine a number ofreceived signals into a single port on SOC 1010.

Similarly, a toroidal coupler 1062 may be used to combine a radar signalcoming from a transmitter port 1012 on DWG segment 1025 with a receivedsignal being provided to a receiver port 1012 via DWG segment 1026 intoa bidirectional signal on DWG segment 1027 that may then be connected toa single radar launching structure for both transmission and reception.Circular/bidirectional couplers are also well known and may rely onaccurate placement of the various ports on the toroidal structure.

DWG structures such as splitter 1061, coupler 1062, and DWG segments1021-1027 may all be fabricated directly on substrate 1051 using varioustechniques, such as 3D printing, for example.

There may be additional ICs mounted on substrate 1051 to control SOC1010 and to provide ADAS functional operations. Communication interfacesmay be provided to communication with other systems in the vehicle, suchas braking systems, steering, engine control, etc.

The entire module 1000 may be encapsulated or otherwise enclosed toprovide mechanical and climatic protection.

FIG. 11 is an end view of an example simple DWG connector 1141 that issuitable for radar signals in the 70-110 GHz band. At this frequency, atolerance of approximately 50 μm is permissible. In this example, thecore member 1121 of a DWG is attached to a housing 1142 that has acavity region 1143 to accept a mating end of another DWG segment. Inthis example, the end of core member 1121 is formed in a pyramid shapeto improve signal coupling with a matching recession in the matingsegment.

FIG. 12 is a more detailed side view of an example connector 1241. Inthis example, DWGs 1221, 1222 are coupled with a Silicone gap fillermaterial 1265. One piece 1270 of the snap connector is mounted on an endof DWG 1221 to form a plug. Another piece 1260 of the snap connector ismounted on an end of stub DWG 1222. The mounting positions of the snapconnector pieces are controlled so that when mated, the deformable gapfiller material 1265 is compressed so as to eliminate most, if not all,air from the gap between DWG 1221 and DWG 1222.

As described in more detail in US 2014-0240187, when two dielectricwaveguides are coupled together, there is likely to be a gap between thetwo DWGs. This gap creates an impedance mismatch that may generatesignificant losses due to radiated energy produced by the impedancemismatch. The extent of the losses depends on the geometry of the gapand the material in the gap. Based on simulations, a square cut buttjoint appears to provide a significant impedance mismatch.

Simulations demonstrate that a spearhead shape such as illustrated at1264 is effective if the taper is done in only two of the sides of theDWG but it is better when the taper is done in the four sides of the DWGto form a pyramidal shape. This taper could also be replaced by aconical shape on four sides or a vaulted shape on two sides, or anyother shape that deflects energy back to the DWG from the signaldeflected by the opposite side cut.

A spearhead, pyramidal, conical, vaulted or similar type shape providesan interface with a very low insertion loss, is easy to implement, ismechanically self-aligning, and is flexible and robust to smallmisalignments. These shapes may all be produced using standardmanufacturing materials and fabrication techniques.

Material in the Gag

In the examples discussed above, the material filling the gap may bejust air, which has a dielectric constant of approximately 1.0. Asdiscussed earlier, the dielectric constant of the core material willtypically be in the range of 3-12, while the dielectric constant of thecladding material will typically be in the range of 2.5-4.5. Themismatch impedance is proportional to the difference of the dielectricconstant between the DWG and the material inside the gap. This meansthat even with the geometry of the socket optimized, an air gap betweenthe DWGs is not an optimum configuration. In order to minimize theimpedance mismatch, a DWG socket may be designed with a rubbery material1265 that has a dielectric constant very close to the dielectricconstant of the DWG core and cladding. A flexible material is desirableto accommodate and fill all the space in the gap. An example of arubbery material with dielectric constant 2.5 to 3.5 is Silicone. Othermaterials with similar characteristics that may be used fall into twotypes: unsaturated rubber and saturated rubber.

Unsaturated rubbers include: Synthetic polyisoprene, Polybutadiene,Chloroprene rubber, Butyl rubber, Halogenated butyl rubbers,Styrene-butadiene Rubber, Nitrile rubber, Hydrogenated Nitrile Rubbers,etc, for example.

Saturated rubbers include: EPM (ethylene propylene rubber), EPDM rubber(ethylene propylene diene rubber),Epichlorohydrin rubber (ECO)Polyacrylic rubber (ACM, ABR), Silicone rubber (SI, Q,VMQ),Fluorosilicone Rubber (FVMQ, Fluoroelastomers (FKM, and FEPM)Viton, Tecnoflon, Fluorel, Perfluoroelastomers (FFKM) Tecnoflon PFR,Kalrez, Chemraz, Perlast, Polyether block amides (PEBA),Chlorosulfonatedpolyethylene (CSM), (Hypalon),Ethylene-vinyl acetate (EVA), etc, forexample.

While a particular configuration of a connecter is illustrated in FIG.12, other embodiments may use any number of now known or later designedconnector designs to couple together two DWGs while maintainingmechanical alignment and providing enough coupling force to maintain adeforming pressure on the gap filler material.

Typically, the deformable material may be affixed to either the male endof DWG 1221 or to the female end of DWG 1222, for example. Thedeformable material may be affixed in a permanent manner using glue,heat fusion, or other bonding technology. However, a thinner layer ofdeformable material may be affixed to the end of both DWG 1221 and tothe end of DWG 1222 such that the gap is filled with two layers ofdeformable material. The male/female orientation of may be reversed inanother embodiment.

Connecter 1141 and 1241 may be manufactured using a 3D printingtechnique to produce a monolithic structure that may then be mountedonto a substrate, such as 951 in FIG. 9 or 1051 in FIG. 10, for example.Alternatively, a 3D printing technique may be used to form DWG socket1141, 1241 along with stub DWG 1221 directly on a substrate.

FIG. 13 is a block diagram of an exemplary radar system on a chip (SOC)1300 that may include multiple radar transmitters and receivers. RadarSOC 1300 may include multiple transmit channels 1310 for transmittingFMCW (frequency modulated continuous wave) RF signals and multiplereceive channels 1320 for receiving the reflected transmitted signals.Further, the number of receive channels may be larger than the number oftransmit channels. For example, an embodiment of the radar SOC 1300 mayhave three transmit channels and four receive channels. Other radar SOCembodiments may have more or fewer transmit and receive channels, forexample. In some embodiments, one SOC may include a set of receivers andanother SOC may include a set of transmitters, for example.

A transmit channel may include a suitable transmitter and antenna. Areceive channel includes a suitable receiver and antenna. Further, eachof the receive channels 1320 may be identical and include a low-noiseamplifier (LNA) 1321 with one or more stages to amplify the receivedsignal, a mixer 1322 to mix the signal generated by the transmissiongeneration circuitry with the received signal to generate an IF signal,a baseband bandpass filter 1323 for filtering the IF signal, a variablegain amplifier (VGA) 1324 for amplifying the filtered IF signal, and ananalog-to-digital converter (ADC) 1325 for converting the analog IFsignal to a digital IF signal. The mixer serves as a down converter thatgenerates an output signal with a frequency equal to the differencebetween the frequency of the inputs received from the low-noiseamplifier and the transmission generation circuitry, both of which areradio frequency (RF) signals. The bandpass filter, VGA, and ADC of areceive channel may be collectively referred to as a baseband chain orbaseband filter chain. Further, the bandpass filter and VGA may becollectively referred to as an IF amplifier (IFA).

The receive channels 1320 are coupled to a digital front end (DFE) andDigital Signal Processor (DSP) system module 1350. The DFE and DSPsystem module may also be coupled to the control (CNTL) module 1340 tocomplete the function of the radar module in both functional and testmodes and external data communication.

A serial peripheral interface (SPI) 1341 may provide an interface forcommunication with the processing unit located in another IC. Forexample, the processing unit may use the SPI 1341 to send controlinformation, e.g., timing and frequencies of chirps, output power level,triggering of monitoring functions, etc., to the DFE and DSP Systemmodule. The radar SOC 1300 may use the SPI 1341, for example, to sendtest data to the processing unit.

The control module 1340 and DFE and DSP System module 1350 may includefunctionality to control the operation of the radar SOC 1300 in normalmode and in test mode.

A 10 GHz or higher frequency modulation synthesizer (FM-Synth) module1330 generates the RF signals that are then multiply by four andprovided to the transmitter channels. The programmable timing engine1331 includes functionality to receive chirp parameter values for asequence of chirps in a radar frame from the control module 1340 and togenerate chirp control signals that control the transmission andreception of the chirps in a frame based on the parameter values. Thechirp parameters are defined by the radar system architecture and mayinclude, for example, a transmitter enable parameter for indicatingwhich transmitters to enable, a chirp frequency start value, a chirpfrequency slope, a chirp duration, indicators of when the transmitchannels should transmit and when the DFE output digital should becollected for further radar processing, etc. One or more of theseparameters may be programmable.

The radio frequency synthesizer (SYNTH) 1332 includes functionality togenerate FMCW (frequency modulated continuous wave) signals fortransmission based on chirp control signals from the timing engine 1331.In some embodiments, the SYNTH 1332 may include a phase locked loop(APLL) with a voltage controlled oscillator (XO).

The clock multiplier 1333 increases the frequency of the transmissionsignal (LO signal) to the LO frequency of the mixers 1322. The clean-upPLL (phase locked loop) operates to increase the frequency of the signalof an external low frequency reference clock (not shown) to thefrequency of the SYNTH 1332 and to filter the reference clock phasenoise out of the clock signal.

The clock multiplier 1333, synthesizer 1332, timing generator 1331, andclean up PLL are an example of transmission generation circuitry. Thetransmission generation circuitry generates a radio frequency (RF)signal as input to the transmit channels and as input to the mixers inthe receive channels via the clock multiplier. The output of thetransmission generation circuitry may be referred to as the LO (localoscillator) signal or the FMCW signal.

The CNTL circuitry 1340 may include one or more temperature sensors andvarious RF/analog measurement components.

FIG. 14 is a flow chart illustrating distribution of radar signalswithin a vehicle. The vehicle may be an automobile, truck, or othermotorized or human powered vehicle. As described in more detail above,one or more radar signals may be generated 1402 in a radar module, suchas module 1300 of FIG. 13.

Radar signals may be transported 1404 between various launchingstructures and ports on the radar module using DWG segments. Asdescribed above in more detail, various couplers and splitters may beused to combine and/or separate signals on the various DWG segments.

Other Embodiments

While the invention has been described with reference to illustrativeembodiments, this description is not intended to be construed in alimiting sense. Various other embodiments of the invention will beapparent to persons skilled in the art upon reference to thisdescription. For example, while a horn antenna was illustrated herein,various configurations of dipole and patch antennas, Vivaldi, or otherknown or later developed launching structures may be used to launch andreceive radar signals through body parts of a vehicle.

While a dielectric waveguide has been described herein, anotherembodiment may use a metallic or non-metallic conductive material toform the top, bottom, and sidewalls of the wave guide, such as: aconductive polymer formed by ionic doping, carbon and graphite basedcompounds, conductive oxides, etc., for example.

A DWG stub and socket assembly may be fabricated onto a surface of asubstrate using an inkjet printing process or other 3D printing process,for example.

While waveguides with polymer dielectric cores have been describedherein, other embodiments may use other materials for the dielectriccore, such as ceramics, glass, etc., for example.

While dielectric cores with a rectangular cross section are describedherein, other embodiments may be easily implemented using the printingprocesses described herein. For example, the dielectric core may have across section that is rectangular, square, trapezoidal, cylindrical,oval, or many other selected geometries. Furthermore, the cross sectionof a dielectric core may change along the length of a waveguide in orderto adjust impedance, produce transmission mode reshaping, etc., forexample.

The dielectric core of the conductive waveguide may be selected from arange of approximately 2.4-12, for example. These values are forcommonly available dielectric materials. Dielectric materials havinghigher or lower values may be used when they become available.

While sub-terahertz signals in the range of 70-100 GHz were discussedherein, DWGs and systems for distributing higher or lower frequencysignals may be implemented using the principles described herein byadjusting the physical size of the DWG core accordingly.

While two example connectors were described herein, other configurationsof connectors that are now known or later developed may be used tofacilitate distribution of radar signals within a vehicle.

While automobiles and trucks were discussed above, embodiments of thedisclosure are not limited autos and trucks. Any type of vehicle thatmay benefit for awareness of nearby objects may benefit from anembodiment of the disclosure. For example, robots, manufacturing andassembly devices, bicycles, etc. may all be regarded as “vehicles” andmake use of an embodiment of the disclosure. Similarly, vehicles formovement of a mobility impaired person, such as a wheel chair orscooter, may benefit from an embodiment of the disclosure. Similarly, a“vehicle” to be used by a blind person for walking assistance may alsobenefit from an embodiment of the disclosure.

Certain terms are used throughout the description and the claims torefer to particular system components. As one skilled in the art willappreciate, components in digital systems may be referred to bydifferent names and/or may be combined in ways not shown herein withoutdeparting from the described functionality. This document does notintend to distinguish between components that differ in name but notfunction. In the following discussion and in the claims, the terms“including” and “comprising” are used in an open-ended fashion, and thusshould be interpreted to mean “including, but not limited to . . . .”Also, the term “couple” and derivatives thereof are intended to mean anindirect, direct, optical, and/or wireless electrical connection. Thus,if a first device couples to a second device, that connection may bethrough a direct electrical connection, through an indirect electricalconnection via other devices and connections, through an opticalelectrical connection, and/or through a wireless electrical connection.

Although method steps may be presented and described herein in asequential fashion, one or more of the steps shown and described may beomitted, repeated, performed concurrently, and/or performed in adifferent order than the order shown in the figures and/or describedherein. Accordingly, embodiments of the invention should not beconsidered limited to the specific ordering of steps shown in thefigures and/or described herein.

It is therefore contemplated that the appended claims will cover anysuch modifications of the embodiments as fall within the true scope andspirit of the invention.

What is claimed is:
 1. A vehicle comprising: a vehicle body having oneor more body parts; a radar module having one or more ports fortransmitting and receiving; a radar antenna positioned adjacent a firstone of the body parts; a dielectric waveguide (DWG) having a dielectriccore member surrounded by second dielectric layer coupled between theradar antenna and a first one of the one or more ports of the Radarmodule.
 2. The vehicle of claim 1, further including: a plurality ofradar antennas positioned adjacent a plurality of locations on one ormore of the body parts; and a plurality of DWGs coupled between theplurality of radar antennas and respective ones of the one or moreports.
 3. The vehicle of claim 2, further comprising a dielectric ratrace splitter with a first port coupled to a port of the radar modulevia a DWG, a second port coupled to a first one of the plurality ofradar antennas via a DWG, and a third port coupled to a second one ofthe plurality of radar antennas via a DWG.
 4. The vehicle of claim 2,further comprising a dielectric circulatory coupler with a first portcoupled to a first port of the radar module via a DWG, a second portcoupled to a second port of the radar module via a DWG, and a third portcoupled to one of the plurality of radar antennas via a DWG.
 5. Thevehicle of claim 1, in which the radar antenna is in contact with asurface of the first body part.
 6. The vehicle of claim 1, in which theradar antenna is spaced apart from a surface of the first body part. 7.The vehicle of claim 1, in which the radar antenna is a horn antenna. 8.The vehicle of claim 1, in which the radar antenna is Vivaldi antenna.9. The vehicle of claim 1, in which the radar antenna is a dipoleantenna.
 10. The vehicle of claim 1, in which the first body part is abumper.
 11. The vehicle of claim 1, in which the first body part is afender.
 12. The vehicle of claim 1, in which the radar module is mountedsuch that a second one of the ports is adjacent one of the body parts.13. A method for distributing radar signals in a vehicle, the methodcomprising: generating a radar signal within a radar module coupled tothe vehicle; and transporting the radar signal from a first port on theradar module to a radar antenna located adjacent a body part of thevehicle via a dielectric waveguide (DWG) having a dielectric core membersurrounded by second dielectric layer.
 14. The method of claim 13,further including transporting multiple radar signals from one or moreports of the radar module to a plurality of radar antennas adjacent oneor more body parts of the vehicle via a plurality of DWGs.
 15. Themethod of claim 14, further including combining two or more radarsignals coupled to two or more ports of the radar module via respectiveDWGs using a coupler.
 16. The method of claim 14, further includingcombining two or more radar signals coupled to two or more radarantennas via respective DWGs using a coupler.
 17. The method of claim13, further including transmitting a second radar signal from a secondport on the radar module through one of the body parts located adjacentthe radar module.